Field
This disclosure relates generally to sensor devices, and more specifically, to using data from accelerometer, gyroscope and magnetometer sensors to determine orientation of a device that produces electromagnetic interference.
Related Art
Recent trends in consumer electronic devices include addition of a variety of magnetic and inertial sensors in portable devices. These sensors include accelerometers to measure device acceleration or gravity, magnetometers to measure magnetic field, and gyroscopes to determine rotational movement. Inclusion and intelligent use of multiple types of sensors has been called “sensor fusion.”
In certain types of applications, knowledge of the orientation of a device with respect to a global frame of reference can be useful. For example, digital still cameras can use both global positioning system (GPS) data and compass orientation data to aid in determining location of and heading towards the subject of a photograph. Compass orientation information can be typically determined by a magnetometer in conjunction with accelerometer readings, but if electromagnetic interference is present, the data provided by the magnetometer can be incorrect. In the case of a digital still camera, electromagnetic interference can be generated by a motor housed within the camera, such as, for example, a lens focusing motor. It is therefore desirable to determine compass orientation data in a manner that compensates for such interference.
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